[Absence of circulating immune complexes and of serum anti-IgG antibodies during ankylosing spondylarthritis].

The sera of 161 subjects hospitalized in a rheumatology department were tested for anti-IgG antibodies using a "PEG radioimmunoprecipitation assay" (RIPEGA), for circulating immune complexes using the liaison test with Clq 125I, and dosage of complement and its metabolites. No significant difference was found between the group of 37 ankylosing spondylitis and the group of 44 control subjects. The results were identical, whatever the form of the disease, be it peripheral or central, and evolutive or non evolutive. On the contrary, the study of the rheumatoid arthritis (47 seropositive and 34 seronegative) provided results in conformity to previous works. The different physiopathogenic origin of these two chronic inflammatory rheumatisms is discussed by the authors.